:root {
  --black: #050505;
  --gray-900: #252525;
  --gray-700: #575757;
  --gray-500: #7a7a7a;
  --gray-200: #dedede;
  --gray-100: #f4f4f4;
  --white: #ffffff;
  --content: 1180px;
  --serif: "Noto Serif KR", "Nanum Myeongjo", "Apple SD Gothic Neo", serif;
  --sans: Pretendard, "Noto Sans KR", "Apple SD Gothic Neo", "Malgun Gothic", sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--white);
  color: var(--black);
  font-family: var(--sans);
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; }
button { font: inherit; }
.skip-link {
  position: fixed;
  z-index: 100;
  top: 8px;
  left: 8px;
  padding: 10px 14px;
  background: var(--black);
  color: white;
  transform: translateY(-160%);
}
.skip-link:focus { transform: translateY(0); }

.site-header {
  height: 84px;
  max-width: var(--content);
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  font-family: var(--serif);
  font-size: 23px;
  font-weight: 800;
  letter-spacing: -.04em;
}
.brand-icon { position: relative; width: 36px; height: 36px; overflow: hidden; }
.brand-icon img { position: absolute; top: 50%; left: 50%; width: 136px; height: 136px; max-width: none; transform: translate(-50%, -50%); }
nav { display: flex; align-items: center; gap: 28px; }
nav a { text-decoration: none; font-size: 14px; font-weight: 700; }
.text-link:hover { text-decoration: underline; text-underline-offset: 5px; }
.header-download { padding: 13px 22px; background: var(--black); color: white; }
.header-download:hover { background: var(--gray-900); }

.hero {
  min-height: 620px;
  border-top: 1px solid var(--gray-200);
  border-bottom: 1px solid var(--gray-200);
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(340px, .75fr);
  align-items: center;
  gap: 80px;
  padding: 48px max(24px, calc((100vw - var(--content)) / 2));
  overflow: hidden;
}
.hero-copy { align-self: center; }
h1 {
  margin: 0;
  max-width: 680px;
  font-family: var(--serif);
  font-size: clamp(48px, 5vw, 72px);
  line-height: 1.22;
  letter-spacing: -.065em;
  font-weight: 800;
}
.lead {
  margin: 30px 0 0;
  color: var(--gray-700);
  font-size: 18px;
  line-height: 1.85;
  letter-spacing: -.025em;
}
.download-area { margin-top: 38px; min-height: 102px; }
.download-button {
  min-width: 290px;
  min-height: 64px;
  border: 1px solid var(--black);
  border-radius: 2px;
  padding: 0 26px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  background: var(--black);
  color: var(--white);
  font-size: 17px;
  font-weight: 800;
  cursor: pointer;
  transition: transform .18s ease, background .18s ease;
}
.download-button:hover { background: var(--gray-900); transform: translateY(-2px); }
.download-button:focus-visible, a:focus-visible { outline: 3px solid #777; outline-offset: 3px; }
.download-button:disabled { cursor: wait; opacity: .66; transform: none; }
.download-button svg { width: 26px; height: 26px; fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
.download-meta { margin: 11px 0 0; color: var(--gray-500); font-size: 13px; }
.download-status { margin-top: 10px; color: var(--gray-700); font-size: 13px; font-weight: 700; }
.download-status[hidden] { display: none; }

.phone-stage { display: flex; justify-content: center; align-self: end; }
.phone {
  position: relative;
  width: 290px;
  height: 570px;
  padding: 10px;
  border: 3px solid var(--black);
  border-radius: 38px 38px 0 0;
  background: #111;
  box-shadow: 0 25px 55px rgba(0,0,0,.13);
  overflow: hidden;
}
.phone img { width: 100%; height: 100%; border-radius: 26px 26px 0 0; object-fit: cover; object-position: top; }
.phone-speaker { position: absolute; z-index: 1; top: 16px; left: 50%; width: 48px; height: 5px; border-radius: 8px; background: #333; transform: translateX(-50%); }

.install { max-width: var(--content); margin: 0 auto; padding: 62px 24px 58px; }
.install h2, .privacy-band h2, .integrity h2 {
  margin: 0;
  font-family: var(--serif);
  font-size: 30px;
  letter-spacing: -.045em;
}
.install > h2 { text-align: center; }
.steps { list-style: none; margin: 48px 0 0; padding: 0; display: grid; grid-template-columns: repeat(3, 1fr); }
.steps li { min-height: 118px; display: grid; grid-template-columns: 48px 1fr; gap: 18px; padding: 0 36px; border-right: 1px solid var(--gray-200); }
.steps li:first-child { padding-left: 0; }
.steps li:last-child { padding-right: 0; border-right: 0; }
.step-number { font-family: var(--serif); font-size: 32px; line-height: 1; }
.steps h3 { margin: 2px 0 10px; font-size: 17px; }
.steps p, .privacy-band p, .integrity p { margin: 0; color: var(--gray-700); font-size: 14px; line-height: 1.75; word-break: keep-all; }
.install-note { margin: 32px 0 0; text-align: center; color: var(--gray-500); font-size: 13px; }

.privacy-band {
  padding: 36px max(24px, calc((100vw - 760px) / 2));
  display: flex;
  align-items: center;
  gap: 24px;
  background: var(--gray-100);
  border-top: 1px solid #ededed;
  border-bottom: 1px solid #ededed;
}
.privacy-band svg { flex: 0 0 44px; width: 44px; fill: none; stroke: var(--black); stroke-width: 1.6; }
.privacy-band p { margin-top: 7px; }
.integrity { max-width: var(--content); margin: 0 auto; padding: 45px 24px; display: grid; grid-template-columns: 1fr 1.15fr; align-items: center; gap: 40px; }
.integrity p { margin-top: 8px; }
.integrity code { padding: 16px 18px; background: var(--gray-100); color: #333; font-size: 11px; line-height: 1.65; overflow-wrap: anywhere; user-select: all; }

footer { min-height: 84px; max-width: var(--content); margin: 0 auto; padding: 0 24px; border-top: 1px solid var(--gray-200); display: flex; align-items: center; justify-content: space-between; }
footer strong { font-family: var(--serif); font-size: 18px; }
footer div { display: flex; gap: 26px; }
footer a { color: var(--gray-700); font-size: 13px; text-decoration: none; }
footer a:hover { text-decoration: underline; text-underline-offset: 4px; }

@media (max-width: 850px) {
  .site-header { height: 72px; }
  .text-link { display: none; }
  .header-download { padding: 11px 16px; }
  .hero { min-height: auto; grid-template-columns: 1fr; gap: 54px; padding-top: 72px; }
  .hero-copy { text-align: center; }
  h1 { font-size: clamp(40px, 11vw, 58px); }
  .lead { font-size: 16px; }
  .phone-stage { max-height: 420px; }
  .phone { width: 250px; height: 490px; }
  .steps { grid-template-columns: 1fr; gap: 0; }
  .steps li { min-height: auto; padding: 26px 0; border-right: 0; border-bottom: 1px solid var(--gray-200); }
  .steps li:last-child { border-bottom: 0; }
  .integrity { grid-template-columns: 1fr; gap: 22px; }
}

@media (max-width: 520px) {
  .brand { font-size: 20px; }
  .brand-icon { width: 31px; height: 31px; }
  .brand-icon img { width: 117px; height: 117px; }
  .hero { padding: 58px 20px 0; gap: 52px; }
  h1 { font-size: 36px; line-height: 1.28; }
  .lead br { display: none; }
  .download-button { width: 100%; min-width: 0; font-size: 16px; }
  .phone-stage { max-height: 410px; }
  .phone { width: 236px; height: 465px; }
  .install { padding: 52px 20px 44px; }
  .privacy-band { align-items: flex-start; padding: 32px 24px; }
  .privacy-band h2, .install h2, .integrity h2 { font-size: 25px; }
  .integrity { padding: 38px 20px; }
  footer { padding: 22px 20px; align-items: flex-start; gap: 20px; }
  footer div { flex-direction: column; gap: 10px; align-items: flex-end; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition-duration: .01ms !important; }
}